1. Field
The present disclosure relates to an organic electroluminescence device (OLED) and a method of manufacturing the same.
2. Description of the Related Art
With the active developments of flat panel displays, an organic electroluminescence device (OLED) is a typical one of surface light-emitting devices that are used for the flat panel displays. The OLED is a light emitting device using electroluminescence of a solid fluorescent material. Since the OLED has a stack layer of materials having different refractive indices, a radiation efficiency of light to the outside (light extraction efficiency) is low due to the reflection at an interface between layers.
In brief calculation of light extraction efficiency, a waveguide light that is confined in a transparent electrode or an organic light-emitting layer so as not to be extractable is about 45% and a substrate waveguide light that is confined in a substrate so as not to be extractable is about 35%. In other words, only about 20% of the light that is emitted may be extracted to the outside.
Accordingly, many solutions have been suggested to improve the light extraction efficiency by providing a means for converting an exit angle of light on a substrate of an OLED. For example, a diffractive lattice structure is manufactured on a substrate so that reflection of light of a particular wavelength is prevented so as to improve extraction efficiency. A lens structure is provided on a substrate surface so that extraction efficiency may be improved. However, since a fine structure is needed in the method, there is a difficulty in a manufacturing process.